pcie_sriov: Reuse SR-IOV VF device instances

Disable SR-IOV VF devices by reusing code to power down PCI devices
instead of removing them when the guest requests to disable VFs. This
allows to realize devices and report VF realization errors at PF
realization time.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-Id: <20240627-reuse-v10-6-7ca0b8ed3d9f@daynix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index 68d30feb8605112d6b3d95d8acf05a7c80f30526..e32a69f3fa82aefe727439fb3822a44a5a23dc5f 100644 (file)
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2895,7 +2895,7 @@ void pci_set_enabled(PCIDevice *d, bool state)
     memory_region_set_enabled(&d->bus_master_enable_region,
                               (pci_get_word(d->config + PCI_COMMAND)
                                & PCI_COMMAND_MASTER) && d->enabled);
-    if (!d->enabled) {
+    if (d->qdev.realized) {
         pci_device_reset(d);
     }
 }

diff --git a/hw/pci/pcie_sriov.c b/hw/pci/pcie_sriov.c
index f0bde0d3fc792efebd4540fd661347e300c9fb73..faadb0d2ea852ea282d2a56c9a56b16da7d122e6 100644 (file)
--- a/hw/pci/pcie_sriov.c
+++ b/hw/pci/pcie_sriov.c
@@ -20,9 +20,16 @@
 #include "qapi/error.h"
 #include "trace.h"
 
-static PCIDevice *register_vf(PCIDevice *pf, int devfn,
-                              const char *name, uint16_t vf_num);
-static void unregister_vfs(PCIDevice *dev);
+static void unparent_vfs(PCIDevice *dev, uint16_t total_vfs)
+{
+    for (uint16_t i = 0; i < total_vfs; i++) {
+        PCIDevice *vf = dev->exp.sriov_pf.vf[i];
+        object_unparent(OBJECT(vf));
+        object_unref(OBJECT(vf));
+    }
+    g_free(dev->exp.sriov_pf.vf);
+    dev->exp.sriov_pf.vf = NULL;
+}
 
 bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
                         const char *vfname, uint16_t vf_dev_id,
@@ -30,6 +37,8 @@ bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
                         uint16_t vf_offset, uint16_t vf_stride,
                         Error **errp)
 {
+    BusState *bus = qdev_get_parent_bus(&dev->qdev);
+    int32_t devfn = dev->devfn + vf_offset;
     uint8_t *cfg = dev->config + offset;
     uint8_t *wmask;
 
@@ -49,7 +58,6 @@ bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
                         offset, PCI_EXT_CAP_SRIOV_SIZEOF);
     dev->exp.sriov_cap = offset;
     dev->exp.sriov_pf.num_vfs = 0;
-    dev->exp.sriov_pf.vfname = g_strdup(vfname);
     dev->exp.sriov_pf.vf = NULL;
 
     pci_set_word(cfg + PCI_SRIOV_VF_OFFSET, vf_offset);
@@ -83,14 +91,34 @@ bool pcie_sriov_pf_init(PCIDevice *dev, uint16_t offset,
 
     qdev_prop_set_bit(&dev->qdev, "multifunction", true);
 
+    dev->exp.sriov_pf.vf = g_new(PCIDevice *, total_vfs);
+
+    for (uint16_t i = 0; i < total_vfs; i++) {
+        PCIDevice *vf = pci_new(devfn, vfname);
+        vf->exp.sriov_vf.pf = dev;
+        vf->exp.sriov_vf.vf_number = i;
+
+        if (!qdev_realize(&vf->qdev, bus, errp)) {
+            unparent_vfs(dev, i);
+            return false;
+        }
+
+        /* set vid/did according to sr/iov spec - they are not used */
+        pci_config_set_vendor_id(vf->config, 0xffff);
+        pci_config_set_device_id(vf->config, 0xffff);
+
+        dev->exp.sriov_pf.vf[i] = vf;
+        devfn += vf_stride;
+    }
+
     return true;
 }
 
 void pcie_sriov_pf_exit(PCIDevice *dev)
 {
-    unregister_vfs(dev);
-    g_free((char *)dev->exp.sriov_pf.vfname);
-    dev->exp.sriov_pf.vfname = NULL;
+    uint8_t *cfg = dev->config + dev->exp.sriov_cap;
+
+    unparent_vfs(dev, pci_get_word(cfg + PCI_SRIOV_TOTAL_VF));
 }
 
 void pcie_sriov_pf_init_vf_bar(PCIDevice *dev, int region_num,
@@ -156,38 +184,11 @@ void pcie_sriov_vf_register_bar(PCIDevice *dev, int region_num,
     }
 }
 
-static PCIDevice *register_vf(PCIDevice *pf, int devfn, const char *name,
-                              uint16_t vf_num)
-{
-    PCIDevice *dev = pci_new(devfn, name);
-    dev->exp.sriov_vf.pf = pf;
-    dev->exp.sriov_vf.vf_number = vf_num;
-    PCIBus *bus = pci_get_bus(pf);
-    Error *local_err = NULL;
-
-    qdev_realize(&dev->qdev, &bus->qbus, &local_err);
-    if (local_err) {
-        error_report_err(local_err);
-        return NULL;
-    }
-
-    /* set vid/did according to sr/iov spec - they are not used */
-    pci_config_set_vendor_id(dev->config, 0xffff);
-    pci_config_set_device_id(dev->config, 0xffff);
-
-    return dev;
-}
-
 static void register_vfs(PCIDevice *dev)
 {
     uint16_t num_vfs;
     uint16_t i;
     uint16_t sriov_cap = dev->exp.sriov_cap;
-    uint16_t vf_offset =
-        pci_get_word(dev->config + sriov_cap + PCI_SRIOV_VF_OFFSET);
-    uint16_t vf_stride =
-        pci_get_word(dev->config + sriov_cap + PCI_SRIOV_VF_STRIDE);
-    int32_t devfn = dev->devfn + vf_offset;
 
     assert(sriov_cap > 0);
     num_vfs = pci_get_word(dev->config + sriov_cap + PCI_SRIOV_NUM_VF);
@@ -195,18 +196,10 @@ static void register_vfs(PCIDevice *dev)
         return;
     }
 
-    dev->exp.sriov_pf.vf = g_new(PCIDevice *, num_vfs);
-
     trace_sriov_register_vfs(dev->name, PCI_SLOT(dev->devfn),
                              PCI_FUNC(dev->devfn), num_vfs);
     for (i = 0; i < num_vfs; i++) {
-        dev->exp.sriov_pf.vf[i] = register_vf(dev, devfn,
-                                              dev->exp.sriov_pf.vfname, i);
-        if (!dev->exp.sriov_pf.vf[i]) {
-            num_vfs = i;
-            break;
-        }
-        devfn += vf_stride;
+        pci_set_enabled(dev->exp.sriov_pf.vf[i], true);
     }
     dev->exp.sriov_pf.num_vfs = num_vfs;
 }
@@ -219,12 +212,8 @@ static void unregister_vfs(PCIDevice *dev)
     trace_sriov_unregister_vfs(dev->name, PCI_SLOT(dev->devfn),
                                PCI_FUNC(dev->devfn), num_vfs);
     for (i = 0; i < num_vfs; i++) {
-        PCIDevice *vf = dev->exp.sriov_pf.vf[i];
-        object_unparent(OBJECT(vf));
-        object_unref(OBJECT(vf));
+        pci_set_enabled(dev->exp.sriov_pf.vf[i], false);
     }
-    g_free(dev->exp.sriov_pf.vf);
-    dev->exp.sriov_pf.vf = NULL;
     dev->exp.sriov_pf.num_vfs = 0;
 }
 
@@ -246,14 +235,10 @@ void pcie_sriov_config_write(PCIDevice *dev, uint32_t address,
                              PCI_FUNC(dev->devfn), off, val, len);
 
     if (range_covers_byte(off, len, PCI_SRIOV_CTRL)) {
-        if (dev->exp.sriov_pf.num_vfs) {
-            if (!(val & PCI_SRIOV_CTRL_VFE)) {
-                unregister_vfs(dev);
-            }
+        if (val & PCI_SRIOV_CTRL_VFE) {
+            register_vfs(dev);
         } else {
-            if (val & PCI_SRIOV_CTRL_VFE) {
-                register_vfs(dev);
-            }
+            unregister_vfs(dev);
         }
     }
 }

diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index fe04b4fafd047d5a3396efacf85dd9e42b4d087b..14a869eeaa71f9496afd1b11277cedc5679cff9e 100644 (file)
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -680,9 +680,4 @@ static inline void pci_irq_pulse(PCIDevice *pci_dev)
 MSIMessage pci_get_msi_message(PCIDevice *dev, int vector);
 void pci_set_enabled(PCIDevice *pci_dev, bool state);
 
-static inline void pci_set_power(PCIDevice *pci_dev, bool state)
-{
-    pci_set_enabled(pci_dev, state);
-}
-
 #endif

diff --git a/include/hw/pci/pci_device.h b/include/hw/pci/pci_device.h
index d57f9ce838848d27ccd7242a6c50f183f85961f9..ca151325085db04e31130cd6ef041d37a9a43942 100644 (file)
--- a/include/hw/pci/pci_device.h
+++ b/include/hw/pci/pci_device.h
@@ -205,6 +205,21 @@ static inline uint16_t pci_get_bdf(PCIDevice *dev)
     return PCI_BUILD_BDF(pci_bus_num(pci_get_bus(dev)), dev->devfn);
 }
 
+static inline void pci_set_power(PCIDevice *pci_dev, bool state)
+{
+    /*
+     * Don't change the enabled state of VFs when powering on/off the device.
+     *
+     * When powering on, VFs must not be enabled immediately but they must
+     * wait until the guest configures SR-IOV.
+     * When powering off, their corresponding PFs will be reset and disable
+     * VFs.
+     */
+    if (!pci_is_vf(pci_dev)) {
+        pci_set_enabled(pci_dev, state);
+    }
+}
+
 uint16_t pci_requester_id(PCIDevice *dev);
 
 /* DMA access functions */

diff --git a/include/hw/pci/pcie_sriov.h b/include/hw/pci/pcie_sriov.h
index aa704e8f9d9ffecf6b947528b1dbea010a286f8b..70649236c18a27c5c4db959ffb68df7239baf6e1 100644 (file)
--- a/include/hw/pci/pcie_sriov.h
+++ b/include/hw/pci/pcie_sriov.h
@@ -18,7 +18,6 @@
 typedef struct PCIESriovPF {
     uint16_t num_vfs;   /* Number of virtual functions created */
     uint8_t vf_bar_type[PCI_NUM_REGIONS];   /* Store type for each VF bar */
-    const char *vfname; /* Reference to the device type used for the VFs */
     PCIDevice **vf;     /* Pointer to an array of num_vfs VF devices */
 } PCIESriovPF;